Concentrator.



T. M. ATKINSON.

GQNGENTRATOR.

21, 1910. 1,049,035. Patented Dec. 31, 1912.

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ml r i In 1 m F. M. ATKINSON.

GONGENTRATOR.

APPLICATION FILED MAY 21, 1910.

1,049,035. Patented Dec.31, 1912.

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specification.

My invention relates to concentrators, and has for its object improvement in the construction and operation of that kind of concentrator which'is used for separating gold from dirt in placer mining. The kind of concentrator here mentioned 1s sometimes called a dry washer, because it performs a separation without-the use of water,.and

by means of an air blast. Devices of this kind work on, the principle that as gold is heavier, than ordinary dirt or sand, a blast of air sufficient to carry away the llghter material will permit the heavier materlal to drop into a suitable receptacle, from which it may be removed and further cleaned-by the ordinary washing process.

In the accom anying drawings, Figure 1 is a side elevation, Fig. 2 is a plan, Fig. 3

is an end elevation, .F 1g. 4 is a plan of the screen, Fig. 5 is a partial plan showing the connection and crank for vibrating the screen, and Fig. 6 is a partial section on line 66 of Fig. 1.

In the said drawings, A represents a wooden frame within which are supported two vertical pipes B and B The u per ends of the pipes 13 and B are unite by a uniting section of pipe, the ends of which are givenreversed curves, as shown at B and 3*. The central portion of the uniting section is horizontal and of larger diameter and is shown at,B Suspended from the lower part of the horizontal portion B and communicating with the same, are two chambers R, in the lower portions of which are drawers R The lower end of the vertical pipe B also is provided with a drawer E, immedately above which are a series of apertures E Adjacent to the pipe B is a chute D, immediately above which is a screen box F provided with a series of screens F Abovethe screen box F is a hopper H, and

the said screen box andthe said hopper are supported on rocking arms G, shown in Figs. 1 and 3. At the lower end of the pi e B is an exhaust fan C, the said pipe being curved so as to unite the saidfan at its center by the bending of the said pipe Specification 0! Letters Patent. 1 Application filed m 21, 1910. Serial no. 562,680.-

drawerE, from whence they removed. Among the particles of fine mate-' B, as shown in Fi '1 and 3. The discharge from the said fan is shown by a ipe B". Supported on an ,exte "185.011 of the rame A is a standard J, on which are the shafts K and L. On .the said shafts are pulleys, a chain, and s rocket wheels, furnishing communication etween the two and a means of drivin the fan 0 and a shaft M, located on the ame work A. The central portion of the shaft M is made into a crank, as shown in Fig. 5, and from this crank a connecting rod M extends to and connects with one of the vertical'supporting rods G of the frame F. The arrangement of these parts is such that when the driving mechanism canon hopper H and screen Patented Dec. 31,1912.

supported in the frame J is driven by power, as illustrated by belts in Fig. 1, the shaft M is rotated and consequently the hopper H and (screen box F arereciprocated. Located in the other pipe B is a damper, illustrated at S, the object of which is to regulate the opening throu h the said pipe B and consequently the v0 ume of air that will be drawn through the pipes 13*, B and their connecting piece by means of the fan O.

The operation is as follows: The powerbeing applied to the' driving mechanism shown in the standard J, the exhaust fan is set in operation, and the hopper and screen frame are vibrated. Material is then depositedin the hopper, which material finds its way through the bottom of the hopper on to the screen. The vibration of the screen sifts the material, permitting the finer particles to dro through the screen from the chute D an pass from the said chute through an aperture D into the tion of the pipe B Here the material meets a current of air drawn by a fan C and entering partly through the aperture E and partly through the aperture- D This current. of 'air passin upward raises the lighter particles, inclu ing'all dust and dirt, carrying the said particles upward and through the pipes to the fan C, and is then discharged outward through the discharge pipe B. The heavier particles, as small nuggets of gold, will drop down into the rial carried upward there is found to be'a lower por maybe readily certain amount of flour gold; that is, very fine particles that are carried upward by the current of air. I find that bymaking the connection from the pipe B to the pipe B the air current sufliciently to latest,

of reverse curves and the central portion large, as illustrated in Fig. l, the change in course of the articles when such change is combined with a larger chamber, as B, tends to cause the particles of gold to settle at certain points in the horizontal section, which points are those represented by the chambers B. As a consequence the line par-' ticles of gold that pass upward are very largely caught in these two chambers and may be removed by means of the drawers R The explanation of the operation of these parts is as follows: The current of air flowing upward inthe left hand pipe B carries with it the smaller particles, including dirt,

dust and fine gold. When the rising air strikes the reverse curve B", the gold being of greater specific gravity than the air, does not readily change its course, but shoot-s across the current of air and impinges upon the lower and inclined portion of the inner 1 part of the curve. Here the particles of gold have their velocity retarded, and thecurrent of air drags or rolls them slowly over this curve, after which they readily fall into the nearest chamber R. Particles which, by reason of fineness, are deflected by not follow this course, or which abound outward after impinging upon this curve, retain or regain their velocity and are carried beyond the first chamber B. After entering the larger central section B, the velocity of the air is checked and these carried-over particles settle and are deposited in the lower part of this enlarged section, principally at the point at which the second chamber R is local? v 1 atl claim is: l

,1. The combination with two vertical pipes, a chute for discharging material into one of said pipes, and an exhaust fan for drawing air through the otherk pipe, of a horizontal section of pipe provided with ends having reversed curves and serving to unite the 'two vertical pipes, said reversed curves being so arranged as to cause particles of gcld'carried therethrough by a current of air to congregate at specified points in the horizontal portion substantially as described, and receiving chambers located at the said points in the horizontal portion.

2. The combination with two vertical pipes, a chute for discharging material into one of said pipes, and an exhaust fan for drawing air through the other pipe, of: a uniting section of pipe connectingtogether the two vertical pipes, said uniting section having its ends formed into reverse curves and thecentral portion of enlarged diameter whereby material of the specific gravity of fine gold carried by a current oi air through said pipe will be normally deposited at s eciuniting section, and receiving chambers lo- 'cated at such points.

' Signed at Chicago this 25 day of April,

fied points in the enlarged portion 0 the 

